Point Source Emissions

North Carolina tracks point source "stack" emissions through its emission inventory program. Larger (Title V) facilities are required to file certified reports annually, and these are reviewed by DAQ staff. Smaller point sources (those holding a permit classification as Small or Synthetic Minor) are now inventoried as part of their permit renewal process (each 5 years), or more often if applying for a permit modification. The Title V facilities account for a vast majority of the emissions of most pollutants on a statewide scale.

The plots that follow for specific pollutants have some limitations and caveats that must be taken into account. Some of these are:

• Emissions are generally estimated, not measured.
• Estimates for some pollutants are based on less than complete data and information, such as reliable emission factors.
• Emission factors change (improve in quality) over time and a historic or retrospective correction is generally not done.
• Not all facilities report every year, thus many of the smaller sources were not included.
• Emissions presented are only for permitted point sources.
• Data systems have changed (improved) over time in ways that have effected the consistent handling and tracking of the information.
• Some (relatively) minor changes have been made in the definition of the pollutants emitted over time (e.g., PM, PM 10, and PM 2.5).
• Prior to about 1993, Title V and other permit classifications were not existent, or at least not consistent with the Clean Air Act (1990) definitions that apply thereafter.
• Some facilities have ceased operation and some new facilities have begun operation.
• Data for smaller sources (permitted as Small or Synthetic minor-post 1992) have not been included in the totals, and
• Other unique situations.

These caveats being given, the data are believed to be reasonable and are certainly the best information
available.

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